Starting gear



Dec. 11, 1934. J. M, TATMANv 1,9s3g952 STARTING GEAR Filed NOV. 7, 1932j@ 25 Eng 5 INVENTOR www Wfw/M ATTORNEY Patented Dec. 11, 1934 UNI-TEDSTATES PATENT CFFICE 16 Claims.

This invention relates'to starting devices for gas engines and the likeand is particularly directed to a power driven starting gear unit whichis automatically uncoupled from the gas engine 5 whenl the startingthereof has been accomplished.

In this type of starting device it has been customary to includea--power means, such as an electric motor, controlled by means of aswitch for rotatinga driving element, as a screw, which driving elementis vthreaded through a pinion for translating the same into mesh with agear of the gas engine, which gear is usually attached to or formedyabout the ilywheel of the gas engine. The r* pinion upon translationinto mesh is rotatively coupled to vthe power by limitation on thetranslative movement of the pinion on the screw. As soon as the gasengine is started, the pinion is automatically withdrawn from mesh withthe ring gearoi the gas engine. This occurs because of the relativelygreater speed imparted to the pinion by the large gear of the startedgas engine as compared with the speed of rotation imparted to the pinionfrom the electric motor, the pinion running back on the threads of therotating screw.

It is the object of this invention'to provide improved Astructure formeshing and driving the pinion of the starting device or gear unit andparticularly an improved shock absorbing device incorporated in thedrive to the pinion which 'functions for taking up rotative or drivingshock as well as cushioning the pinion and shifted elements at the limitof meshing and unmeshing translative movements. More specifically,vcertain of the present improvements are in connec- 35" tionwith animproved mounting and connection for a driving spring which takes up thepreviously mentioned rotative and translative shocks as deliveredthrough the pinion, wherein the assembly and mounting of the spring inthe driving unit is extremely compact and easily accomplished.

It is a further object of this invention to provide an improved mountingand arrangement of the driving spring, whereby the drive is balanced andthe driving torque is evenly distributed, and wherein structure isincluded -fcr preventing undue deformation or disalignment of thespring.

It is a still further object to provide an improved abutment forlimiting meshing movement of the pinion, which abutment is exceedinglyeasy to install and positive in function.

It is a still further object to provide improved assembly means for thepinion and overbalancing weight usually associated therewith, whereby55; these parts are positively locked together by a very simple andeffective device and assembly operation.

Other objects and further advantages will be more fully apparent from adescription of the accompanying drawing, in which:

Figure 1 is a side view of the electric motor and starting unit showingthe starter unit casing in section and the pinion'of the starting unitin section for generally lustrating the mounting and arrangement of thestarting unit.

Figure 2 is a longitudinal sectional view of the starting unit, showingthe details thereof.

Figure 3 is aY sectional View taken on line 3 3, Figure 2, detailing theattachment means for the driving spring sections.

Figure 4 is asectional view taken on line 4 4, Figure 2, showingtheoverbalance weight in face view.

Figure 5 is a detail View of one of the spring sections showingl itremoved from the unit.

Figure 6 is a longitudinal sectional view of the overbalance weight andpinion of the fabricated type, showing these parts just prior toassembly.

Figure 7 is a longitudinal sectional View of the assembled pinion andweight fabricated of the 25 parts shown in Figure 6.

The starting gear unit of this invention generally described is drivenby meansoi an electric motor 10 and is arranged for driving engagementwith the ring gear 1l located on the fly wheel of the gas engine. Thedetails of the gasengine and the electric motor are not disclosed exceptto indicate that'the moto-r isfcontrolled by means of a starter switchl2 which generally includes a depressible control'button or"conventional design (not shown) located on the floor board in the motorcar and operating the plunger 13 of the switch shown at the top of theelectric motor.

At the driving end of the motor 10 an end casing or starter unit housing14 is attached, this casing or housing providing an outer bearing 15 forthe motor shaft driving extension 16. The starting gear unit is mountedentirely within this casing 4, and is open to the exterior toward theouter end of the casing through agear clearance opening 17 in thecasing. The starting apparatus is bolted to the gas engine by means ofan exterior attachment flange 18 formed intermediate of the length `50of the end casing, the extreme end of the casing being extended intovthe region of the ily `Wheel and the slot or opening `1'? providingclearance for the ring gear on the motor fly Wheel.

The driving connection for the starting gear f of.

unit consists of a collar 19 keyed to the drive shaft by means of thekey 20. The driving collar 19 is further attached to the drive shaft bymeans of a set screw 21 which includes a tip on its inner end extendedinto the shaft. A headed screw-threaded sleeve 22 is loosely mounted onthe drive shaft extension and is adapted for longitudinal and rotativemovement relative to the shaft during shock absorbing movements as willbe hereinafter described.

The driving collar or head 19 is connected to the adjacently disposedhead 23 of the sleeve by means of coil spring sections 24-24, thesespring sections providing yielding driving connection between the partsas well as accommodating for longitudinal shifting of the screw-threadedsleeve during meshing and unmeshing of and limitation on the translativemovement of the pinion 25 screw-threaded thereon. The pinion has limitedmovements on the screw-threaded sleeve in both directions and at itsouter position is adapted to be fully meshed with the ring gear 1l ofthe gas engine.

The outward movement of the pinion after mesh is limited by means of asplit ring 26 formed of round wire fixed in an annular recess 27 at theextreme outer end of the screw-threaded sleeve, this groove beingsemi-circular in cross section and the ring 26 therefore projecting fromthe surface of the screw-threaded sleeve. The outer end face of thepinion includes an annular groove 28 formed as a counterbore and on thesame cross-sectional radius as the radius of the semi-circular annulargroove of the screwthreaded sleeve and thereforeV adapted to rlt snuglyover the split ring. The center of the wire of the split ring is alignedwith the tops of the screw threads of the sleeve and the ring is ofsufficient gage to extend well above the surface of the sleeve. Thisabutment or limit stop for the pinion is extremely sturdy and cannot bedisplaced by heavy impacts delivered as the pinion forcibly reaches itsouter limit of movement since the action of the pinion thereagainst isto force the split ring into the groove.

Inward or unmeshing movement of the pinion is limited by the engagementof the ends of the pinion threads with the ends 30 of the threads of thescrew-threaded sleeve. A triple thread is used providing a triple stop.The threads of the screw-threaded sleeve are discontinued a sufficientdistance from the inner side of the screw-threaded sleeve head toprevent abutment of the pinion and weight therewith.

The pinion carries an overbalance weight 29 on its inner side tending tohold the pinion against rotation as the screw-threaded sleeve isrotated, thereby causing translation of the pinion, the principleinvolved in the utilization of this weight being well understood in thisart. 'Ihe overbalance weight is formed by the provision of a concentricflange on the pinion which is eccentrically counterbored (see Figure 4),leaving a ange mass on one side of the aXis suitable for the purposedescribed.

The driving collar 19 and the head 23 of the sleeve are coupled togetherby two spring sections 24, each of the construction shown in Figure 5.The coils of each spring section are sufliciently spaced to permit aninterspiralling or coiling of the spring sections in which the coils aresuitably spaced for free action. Each section includes eyelets orterminal clips 31 at its respective ends and on the same side of theaxis there- Consequently through the use of the two spring sectionsthere are four points of attachment for the driving spring unit, two toeach element, namely, the driving power and the headed sleeve and atdiametrically opposite sides. The eyelets or terminal clips of thesprings are disposed about integral studs 32 formed from the peripheralsurfaces of the driving collar and the head of the sleeve by milling. Aflat portion 33 is milled for each clip by means of a rotating cutterleaving a central portion forming the stud. Sleeves or rings 34 areforced over the peripheral surfaces of the driving collar and the headof the sleeve when the eyelets or terminals have been set about thestuds, these rings being firmly xed in place by any desired means.

As the driving spring is active and driving torque is taken up therein,the spring tends to deform `or contract inwardly. For the purpose oflimiting this collapsing or inward movement of the spring coils a core35 consisting of a coil spring formed of square wire is mounted on theaxis of the shaft between the driving collar and the head of the sleeveand is supported on a hub extension 36 of the driving head. This springcore is coiled in the opposite direction to that of the coils of thedriving spring so that the action of the driving spring thereon will beto further wind up the coil rather than to spread the same which wouldpermit interference between the coils of the inner and outer springs.Since both the driving coil spring sections and the core for supportingthe same are longitudinally compressible, meshing and unmeshing of thepinion or limitation on the travel of the pinion causing longitudinalmovement of the screw-threaded sleeve in either direction will beaccommodated.

As shown in Figures 6 and "I, the pinion may be fabricated in twopieces, a weight element 37 and a pinion element 38. For this purposethe ends of the teeth of the pinion are milled to produce tangs or spurs39, an undercut groove 40 and an inclined face 4l forming these tangs.The undercut groove is at an angle inwardly toward the axis of thepinion and the extreme outer end of the body of the pinion is of greaterdiameter than the diameter of the pinion at the base of the teeth tocorrespond to the angle of the undercut.

The weight element includes a bore 42 which is of the same diameter asthe enlarged end of the pinion and has a circular groove 43 cut in itsinner face. As the weight is forced on the end of the pinion the metal44 between the groove 43 and the bore 42 of the weight is entered intothe undercut grooves 40 of the teeth and is forced into the anglethereof, thus cleating and swaging the metal over the enlarged pinionend. The tangs are thus forced into the groove and further lock theparts together (see Figure 7).

Having described my invention, I claim:

1. A starter gear unit, comprising, a power shaft, a driving collarfixed to said shaft, a pinion mounted on said power shaft, ascrew-threaded element for translating said pinion on said power shaft,and intercoiled' coil springs disposed about the shaft, each springhaving terminals at each end formed to provide eyelets having their axesdisposed at right angles to and on the same side of the aXis of the coilspring, `said springs being arranged so that the eyelets of each springare oppositely disposed relative to the eyelets of the other of saidsprings, said nut and adjacent end of said screw-threaded element havingintegral pins on ktheir respective peripheries for receiving saideyelets.

n -2,. A starter gear unit, comprising, a power shaft, a driving collarfixed to said shaft, a pinion slidably and rotatablymounted on saidpower shaft, a nut having a screw-threaded connection with said pinionfor translating said pinion on said power shaft, coil springs disposedabout the shaft, each spring having terminal eyelets at each end, theaxes of which are disposed at right angles toand on the same side of theaxis of the coil spring, said springs being arranged so that the eyeletsof each spring are oppositely disposed relative to the eyelets of theother of said springs, said nut and collar having integral studs cut intheir peripheries about which the respectiveeyelets are mounted.

3. A starter gear adapted for driving a gear of an internal combustionengine, comprising, a power driven shaft, a screw-threaded sleevetranslatably and rotatably mounted on the power shaft, a pinionscrew-threaded on said sleeve for translation into mesh with the gear ofthe internal combustion engine for rotation thereof, a driving elementxed on the driving shaft, a coil spring having its ends attached to thedriving element and the screw-threaded sleeve respectively, and a coilspring mounted within and coaxially with the first coil spring, saidinner spring coiled in the opposite direction to the coiling of theouter spring and serving as a core for supporting the outer spring whenthe outer spring is under driving load.

4. In combination with a relatively high-speed motor shaft and itsdriven gear, a self-contained starting device therefor, comprising, arelatively low speed motor shaft forming a mounting for the assembly, adriving pinion and screw sleeve unit translatable on the shaft forengaging and disengaging the gear, a driving unit comprising twomembers, one member keyed to the motor shaft and the other driving thepinion, means limiting the longitudinal travel of the pinion, and aspring assembly, rotatably connecting the two members of the drivingunit and cushioning the gear intermeshing and releasing impact, saidspring assembly including intercoiled sections, each of which has aterminal at each end on the same side of the axis thereof and attachedto the respective driving members, the terminals of the respectivespring sections being diametrically oppositely disposed.

5. In a starter gear including an axial mounting, a yieldable drivingunit for the gear, comprising, spaced collars mounted on said axialmounting, a coil spring disposed about said axial mounting between andagainst said collars, said spring having its ends connected to saidcollars respectively, each collar including an integral stud formed inits periphery and each terminal of the spring including an eyeletdisposed about the respective adjacent stud, and axially disposed meansfor yieldably supporting said spring when under load.

6. In a starter gearincluding an axial mounting, a yieldable drivingunit for the gear, comprising, spaced collars mounted on said axialmounting, coil springs disposed about said axial mounting between andagainst said collars, said springs intercoiled and each having its endsconnected to said collars respectively, each collar includingdiametrically oppositely disposed studs integrally formed in itsperiphery each of said springs including eyelets forming terminals ateach end of the spring on the same side of the axis thereof, theterminals of each spring engaged over said studs whereby each spring hasits terprising, spaced collars mounted on said axial y mounting, coilsprings disposed about said axial mounting between and against saidycollars, each spring having its ends connected to said collarsrespectively, each collar including diametrically oppositely disposedstuds formed in its periphery and each terminal of each spring includingan eyelet disposed about the respective, adjacent stud, and a ringsecured over each collarfor maintaining the spring terminals` inposition about the studs. i

8. In a starter gear including an axial mount,- ing and a pinion mountedthereon, a driving unit adapted to drive said pinion and comprisingspaced collars mounted on said axial mounting, said collars having flatportions thereon and studs extended from said flat portions, and a coilspring disposed between said collars and having eyelets at its endsseated on said flat portions of the respective collars.

9. In a starter gear including an axial mounting and a pinion mountedthereon, a pinion driving unit comprising spaced collars mounted on saidaxial mounting, and intercoiled coil springs disposed between saidcollars and each having terminals at each end for connecting the same tothe respective collars, the terminals at corresponding ends of eachspring being attached to the particular collar at diametrically oppositepoints thereof.

l0. In a starter gear unit, a driving element, a

pinion, a driven element for driving and translating said pinion, saiddriving element and said driven element including circumferentialiianges, diametrically oppositely disposed integral studs extending fromfiat portions on the peripheries of said flanges, coil springs disposedbetween said flanges including terminal eyelets engaging the respectivestuds, and rings engaged over said circumferential flanges for lockingthe eyelets upon the studs.

' 11. In a starter gear unit, a driving element, a pinion, a drivenelement for rotating and translating said pinion, a coil spring disposedbetween and attached to the driving and driven elements respectively,and a yieldable core mounted coaxially within said spring between thedriving and driven elements, said core being yieldable longitudinallyand inwardly under the lateral and longitudinal movement of the coilspring between the driving and driven elements.

12. In a starter gear unit, a driving element, a pinion, a drivenelement for driving and translating said pinion, said driving elementand said driven element including circumferential Iianges, diametricallyoppositely disposed integral studs extending from flat portions on theperipheries of said flanges, and intercoiled springs disposed betweensaid flanges, each spring including terminal eyelets engaging therespective studs, and the eyelets of each spring circumferentiallyspaced re1- ative to those of the other spring.

13. In a starter gear unit, a driving element, a pinion, a drivenelement for rotating and translating said pinion, a coil driving springdisposed between and attached to the driving and driven elementsrespectively, and a coil spring mounted co-axially within said drivingspring, said spring reversely wound relative to the driving spring andadapted to support the driving spring when the driving spring is underload.

14. In a starter gear unit, a driving element, comprising, a pinion, anoverbalance element, the adjacent ends of teeth of the pinion beingundercut downwardly and said overbalance element including a bore and anannular groove in its inner face providing a flange between the grooveand the bore of the element, whereby the ange is engaged in the undercutgroove of the pinion teeth when the parts are assembled.

15. In a starter gear unit, a driving element; comprising, a pinion, anoverbalance element, the adjacent ends of each tooth of the pinion beingundercut downwardly and pointed, and said overbalance element includinga bore and an annular groove in its inner face providing a flangebetween the groove and the bore of the element, whereby the flange isengaged in the undercut groove of the pinion teeth and the ends of theteeth are engaged in the annular groove when the parts are assembled.

16. In a starter gear including an axial mount- 3 ing and a pinionmounted thereon, a driving unit adapted to drive said pinion andcomprising spaced collars mounted on said axial mounting, said collarshaving iiat portions thereon, integral studs extended from said flatportions, and coil springs disposed between said collars and havingeyelets at their ends engaged about the studs and seated upon the flatportions of the respective collars.

JAMES M. TATMAN.

